Legal concerns re: Charite disc

[ADR in the USA]

Rather than posting in two different threads regarding this topic, I opted to post here.

As a candidate for multi-level ADR, I hate to hear negative news regarding ADR because a) it brings up fear, b) I know how difficult ADR surgeons have worked to get FDA approval, c) alot of folks have hopes that could be crushed and d) a lot of folks have had this procedure and have hope for the future.

If I could turn your attention to http://www.istreamplanet.com/srs/def...a&conf=2&edi=6 (It is the Scoliosis Research Society's 12th International Meeting on Advanced Spinal Techniques Thursday session). You will see a link for the 8:08 am meeting featuring Steven Kurtz. His presentation is entitled Polyethylene Wear Analysis of Retrieved Total Disc Arthroplasty.

I must admit, I was hopeful when the FDA approved the Charite in the US. Now, after viewing Kurtz's presentation, I must admit that, in my humble opinion, the Charite is flawed in design and should be recalled. It's a shame that so many doctors, whom have worked so hard, should disolve the marriage they have with the manufacturer, but the long term results are in and the Charite design, independent of surgical skill, is causing a great deal of harm do to polyethylene wear.

This is what causes me great concern with regard to, if the FDA gives me a choice, my choice between Prodisc and Maverick. The Prodisc uses polyethylene. Whether it's design addresses the wear problem is yet to be seen. Then again, the Maverick uses a keel design, which, in an email conversatin with Dr. Zeegers, appears to concern him.

Back in 1981 when I had fusion for scoliosis with Harrington Rod placement, I was led to believe by a "very prominent" surgeon that this would fix the problem. A new generation of spinal surgeons made an entire career out of doing "salvage surgeries" on folks with "flatback syndrome"- a medical condition where DDD adjacent to the fusion occurs, because these discs must pick up the load of the fused discs. I am not aware of any lawsuits against the manufacturer of the Harrington Rod because surgeons refused to acknowledge that the Harrington Rod was flawed in design until the statute of limitations wore out. I don't think you will see this history repeat itself with regard to ADR.

[Alastair]

I have listened to a lot of the discussions, the one about the failing Charitee polythene disk, if you notice that report is from Europe(Maastrict). Professor Van Ooij (who does only fusions) I suspect, had a big hand in that.I have known him take an ADR out simply on the basis of "Its not a fusion". He goes to many conferences and shouts "ADR is not the way ahead do fusions" and then sits down and we can all get on with what we came to do and hear. -- lol

It's always very difficult to look back at research as this was from 1991 to 2001, many of the components including the polythene disk have been improved and revised, also surgeons have improved their techniques and operating theatre techniques have made giant steps forward making the surgeries for ADR even better.

Subsidence problems are now easily resolved and a lot of those failures you will see the words subsidence appear

Also of course all the surgeons were on a "learning curve" and if you notice it says that surgery times improved, patient recovery improved even after as little as 15 surgeries.

I found it quite fascinating and interesting that the scoliosis Society should be heading this particular research and discussion because generally, scoliosis can be a very good reason for not doing ADR.

For all 40 nations that to post here, we have got to pay attention to the fact that this is the USA on a learning curve, where Europe has been doing this since 1984.

Other countries will learn by the historical results of others I am sure.

Folks try not to scare yourselves if you watch this one
Best,
Alastair

[Harrison]

Well, I am sorry to hear that you want to recall a technology that has helped thousands of people reclaim their lives – helping them return to work, love and play!

We’ve talked quite a bit about Dr. Kurtz' paid contract with Medtronic on this forum. I think both Medtronic and Exponent did a good job with most of the aspects of their investigation, but it was hardly an altruistic project! Lest we forget the role of Medtronic in the “device arena,” check out this FAQ on Medtronic’s aggressive business strategy:

http://adrsupport.org/eve/forums/a/t...1/m/6041063881

If you have any questions regarding the design of the Charite’, then what are they?! In the meatime, we’ve really drilled into some details in the past few years of discussions. Here are a few of the past topics here:

Research for Hard Core Plastics Geeks
http://adrsupport.org/eve/forums/a/tpc/f/7501036081/m/1...131027081#1131027081


Publication: Wear Particles and ADR
http://adrsupport.org/eve/forums/a/tpc/f/7501036081/m/8...001029281#5001029281


Technical Article on High Grade Medical Plastic
http://adrsupport.org/eve/forums/a/t...9461086081/p/1

Please read them carefully, then share your questions and concerns with us. Thanks.

[annapurna]

Avoiding questions of Dr. Kurtz affiliations, I have to speak to his research and conclusions. I've listened to his talk and feel that the conclusions drawn within the discussion are slightly weak, but entirely justified if seen in light of the study size. What isn't justified is the conclusions asserted outside of the study and the conclusions drawn by ADR in the USA.

First, you need to think about the implications of the study participants. Every one of the participants had serious problems leading to misalignment of the ADR and one of the patient had to have two revisions. An appropriate conclusion here is that if you implant the ADR wrong or end up with it misaligned, the ADR will fail faster than it should. Osteolysis, cited in two incidents, could have been due to wear particles but the presentation of the data doesn't make it clear as to whether there was misalignment issued due to osteolysis or the misalignment occured leading to wear and osteolysis, which then accelerated the misalignment.

Second, the study looked at an incredibly small number of participants. Bertagnoli or Zeegers could easily implant more ADRs in a busy week than this study examined. Another way of stating the study's conclusions in light of this would be "if your ADR isn't a success and if it doesn't suceed due to misalignment issues, you may end up with accelerated wear which could lead to osteolysis or failure of the disc core." The odds are likely better for being hit by a car and not being around to care about accelerated wear over having your ADR fail due to the mechanisms suggested by this study.

Third, all prostheses are fundamentally flawed when compared with the original equipment. Ideally, no one would need them but things happen and people do. You need to pursue what you feel to be the best option available to you at the time you need it but you also need to recognize that any option you chose, from ignoring the problem to the most advanced prosthetic, there will be some compromise inherent in the decision.

[Alastair]

Um! I didn't like to suggest that the USA doctors did not have the ADR correctly implanted, because they seem to have enough on their hands at the moment.

The ADR disk alignment equipment now is vastly superior to what it was previously, and I did think that maybe some of the plastic disc problems could have been caused by mis -alignment of the prosthesis.

Obviously at the back of the minds of the doctors, is the huge burden of litigation against the doctors insurance should ADR not go well for them. I don't know if people looked at the cost with regards to ADR as against a fusion and the hospital stay, and that was quite interesting.

Sorry Harrison I don't understand you talking about me going backwards in time in technology.
Best,
Alastair

[annapurna]

Originally posted by Alastair:
Um! I didn't like to suggest that the USA doctors did not have the ADR correctly implanted, because they seem to have enough on their hands at the moment.

I'm not sure that the study suggested that. Given the implantation dates, I wasn't sure that it wasn't all European surgeons.

[Alastair]

If you listened to the commentary it was all USA surgeons as far as I could tell starting with Dr Regan,I could be wrong though.
Best
Alastair

[Harrison]

Alastair, my comments were directed to the topic opener (sorry), ADR in the USA.

AnnaPurna, well said -- as always!

[tmont]

I watched the presentation and of course it gives pause and cause for concern, but as Annapurna said, nothing compares to the original hardware and I don't think anything ever will. Some of those removed prostheses looked liked sledgehammers had been taken to them--makes me wonder about the implantation process and the sizing upon implantation--in other words, the human factor.

I still have to express concern over the core material and wear debris issues though, and this presentation did mention local inflammatory reaction due to polyethylene wear debris. This doesn't just concerne the Charite, but even the discs I'm considering for my cervical procedure. I was talking behind the scenes with someone who mentioned ceramic devices in the works, which would generate no wear debris and no imaging artifact--this would appear to be the next step in development but for now I haven't been able to find much about this on the web.

To end on a 'positive' note for Rich, who thinks I hate the Charite ...found this today:

August 1, 2006

In Vitro Wear Assessment of the Charite Artificial Disc According to ASTM Recommendations.

Biomechanics

Spine. 31(17):1900-1910, August 1, 2006.
Serhan, Hassan A. PhD; Dooris, Andrew P. PhD; Parsons, Matthew L. MS; Ares, Paul J.; Gabriel, Stefan M. PhD, PE
Abstract:
Study Design. Biomechanical laboratory research.

Objective. To evaluate the potential for Ultra High Molecular Weight Polyethylene (UHMWPE) wear debris from the Charite Artificial Disc.

Summary of Background Data. Cases of osteolysis from artificial discs are extremely rare, but hip and knee studies demonstrate the osteolytic potential and clinical concern of UHMWPE wear debris. Standards for testing artificial discs continue to evolve, and there are few detailed reports of artificial disc wear characterizations.

Methods. Implant assemblies were tested to 10 million cycles of +/-7.5[degrees] flexion-extension or +/-7.5[degrees] left/right lateral bending, both with +/-2[degrees] axial rotation and 900 N to 1,850 N cyclic compression. Cores were weighed, measured, and photographed. Soak and loaded soak controls were used. Wear debris was analyzed via scanning electron microscopy and particle counters.

Results. The average total wear of the implants was 0.11 and 0.13 mg per million cycles, before and after accounting for serum absorption, respectively. Total height loss was approximately 0.2 mm. Wear debris ranged from submicron to >10 [mu]m in size.

Conclusions. Under these test conditions, the Charite Artificial Disc produced minimal wear debris. Debris size and morphology tended to be similar to other CoCr-UHMWPE joints. More testing is necessary to evaluate the implants under a spectrum of loading conditions.

(C) 2006 Lippincott Williams & Wilkins, Inc.

Trace